CN115347266B

CN115347266B - Wet crushing and recycling method and device for waste lithium ion batteries

Info

Publication number: CN115347266B
Application number: CN202211276145.5A
Authority: CN
Inventors: 吴宇鹏; 魏文添; 刘雅婷; 陈传林; 林海强; 韩恒; 苏俊; 黄兵
Original assignee: Guangzhou Tinci Materials Technology Co Ltd
Current assignee: Guangzhou Tinci Materials Technology Co Ltd
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2023-01-06
Anticipated expiration: 2042-10-19
Also published as: WO2024083107A1; CN115347266A

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a wet crushing and recycling method and device for waste lithium ion batteries. The recovery method comprises the following steps: crushing the waste lithium ion battery in a first solution; then carrying out buoyancy separation on the crushed first mixture; pretreating the second mixture; distilling the first filtrate and/or the second filtrate under reduced pressure; volatilizing the third mixture in inert gas; post-treating the fourth mixture, and condensing the first mixed gas and/or the second mixed gas; carrying out liquid separation treatment on the first mixed solution and rectifying the second mixed solution; and meanwhile, the filtered filtrate is recycled, so that the solution is treated in the wet crushing process, and the lithium salt and the organic solvent in the solution are efficiently recovered. The problem of the solution in the broken recovery process of old and useless lithium ion battery wet process handle improperly, lead to environmental pollution is solved. The invention also provides a wet crushing and recycling device for the waste lithium ion batteries.

Description

Wet crushing and recycling method and device for waste lithium ion batteries

Technical Field

The invention relates to the technical field of lithium ion batteries, in particular to a wet crushing and recycling method and device for waste lithium ion batteries.

Background

The lithium ion battery has the advantages of high voltage, small volume, high specific energy, small self-discharge, high safety and the like, and is widely applied to the fields of consumer electronics, electric vehicles, industrial energy storage and the like. With the rapid development of the new energy automobile industry, the stock keeping amount of new energy automobiles in China is rapidly increased, the retirement amount of lithium ion batteries is continuously increased, according to statistics of solid waste and chemical management technical departments of China ministry of ecological environment, the total amount of the retired lithium ion batteries in China is about 20 ten thousand tons in 2020, and the retirement amount of the lithium ion batteries in China is estimated to exceed 70 ten thousand tons in 2025. Therefore, recycling of spent lithium ion batteries is also becoming important.

At present, the waste lithium ion battery is generally crushed and recycled by a dry method. The dry crushing has the risk of easy explosion in the crushing process, the electrolyte volatilizes and the generated dust easily causes pollution to the environment, and the wet crushing recovery method can well solve the problems and greatly improve the production efficiency and the recovery rate. However, since the wet crushing recovery process needs to add a liquid, the whole process needs to be performed in a solution, and the solution contains an electrolyte in the waste lithium ion battery, which is likely to cause environmental pollution if the solution in the recovery process is not properly treated.

Disclosure of Invention

The invention provides a wet crushing and recycling method and device for waste lithium ion batteries, and aims to solve the problem of environmental pollution caused by improper treatment of a solution in a recycling process in a wet crushing and recycling process of the waste lithium ion batteries.

In a first aspect, the invention provides a wet crushing and recycling method for waste lithium ion batteries, which comprises the following steps:

s11, crushing the waste lithium ion battery in a first solution to obtain a first mixture; wherein the first mixture comprises water, an organic solvent of an electrolyte of the waste lithium ion battery, and a first lithium salt;

s12, introducing gas into the first mixture, stirring, and performing buoyancy separation to obtain a second mixture and a plastic film respectively;

step S13, performing pretreatment on the second mixture to obtain a shell, a pile head, first filtrate, second filtrate, copper foil, aluminum foil and a third mixture;

step S14, carrying out reduced pressure distillation on the first filtrate and/or the second filtrate to obtain a first mixed gas and a fourth mixture;

s15, volatilizing the third mixture in inert gas to obtain second mixed gas and black powder;

step S16, carrying out post-treatment on the fourth mixture to respectively obtain a second lithium salt, calcium fluoride and calcium phosphate;

step S17, condensing the first mixed gas and/or the second mixed gas to obtain a first mixed liquid; wherein the first mixed liquid comprises water and the organic solvent;

step S18, carrying out liquid separation treatment on the first mixed solution to respectively obtain a second mixed solution and a third mixed solution; wherein the volume of the organic solvent in the second mixed solution is larger than that of water, and the volume of the organic solvent in the third mixed solution is smaller than that of water;

and S19, rectifying the second mixed solution to respectively obtain the organic solvent and water.

In some embodiments, the temperature of the reduced pressure distillation in the step S14 is 30 to 150 ℃, and the pressure of the reduced pressure distillation is 0.01 to 0.1MPa.

In some embodiments, the temperature of the volatilization in the step S15 is 50 to 200 ℃, and the time of the volatilization is 20 to 180min.

In some embodiments, the temperature of the rectification in the step S19 is 30 to 150 ℃.

In some embodiments of the present invention, the,

the step S12 includes:

a step S121 of introducing the first mixture into a buoyant sorting device that discharges gas from a bottom thereof and generates rising bubbles in the first mixture;

step S122, stirring the first mixture by a stirrer of the buoyancy sorting device;

and S123, separating the floating plastic film from the first mixture by using a separating scraper of the buoyancy separation device to respectively obtain the second mixture and the plastic film.

In some embodiments of the present invention, the,

the step S13 includes:

step S131, performing hydrodynamic sorting on the second mixture to respectively obtain a first pretreatment mixture and a second pretreatment mixture; wherein the first pre-treatment mixture comprises the shell and the pile head;

step S132, filtering the second pretreatment mixture to obtain the first filtrate and a third pretreatment mixture;

step S133, adding the third pretreatment mixture into a second solution for ball milling to obtain a fourth pretreatment mixture;

step S134, screening and sorting the fourth pretreatment mixture to obtain a fifth pretreatment mixture and a sixth pretreatment mixture; wherein the fifth pretreatment mixture comprises the copper foil and the aluminum foil;

step S135, filtering the sixth pretreatment mixture to obtain the second filtrate and the third mixture.

In some embodiments, in step S133, the weight ratio of the third pretreatment mixture to the second solution is 1:1 to 10, the ball milling time is 20 to 120 minutes, and the ball milling speed is 100 to 500 rpm.

In some embodiments of the present invention, the,

the second solution in the step S133 includes water and/or the second filtrate.

In some embodiments of the present invention, the,

the step S16 includes:

step S161, adding an acid solution into the fourth mixture for dissolving, and filtering to obtain a first post-treatment solution;

step S162, adding soluble carbonate or soluble phosphate into the first post-treatment solution for reaction, and filtering to obtain a second lithium salt and a second post-treatment solution respectively;

and step S163, adding calcium hydroxide into the second post-treatment solution for reaction, and filtering to obtain the calcium fluoride, the calcium phosphate and a third post-treatment solution.

In some embodiments of the present invention, the,

the first solution in step S11 includes one or more combinations of water, the first filtrate, the third mixed solution, and the third post-treatment solution.

In some embodiments of the present invention, the,

the inert gas in the step S15 includes one or more of nitrogen, helium, argon, and carbon dioxide.

In some embodiments of the present invention, the,

in the step S17, the condensation temperature is-20 to 20 ℃.

In a second aspect, the present invention provides a wet crushing and recovering device for waste lithium ion batteries, including:

the crushing device is used for crushing the waste lithium ion battery in a first solution to obtain a first mixture; wherein the first mixture comprises water, an organic solvent of an electrolyte of the waste lithium ion battery, and a first lithium salt;

the buoyancy separation device is used for introducing gas into the first mixture, stirring the mixture, and respectively obtaining a second mixture and a plastic film through buoyancy separation;

the pretreatment device is used for pretreating the second mixture to obtain a shell, a pile head, first filtrate, second filtrate, copper foil, aluminum foil and a third mixture;

the reduced pressure distillation device is used for carrying out reduced pressure distillation on the first filtrate and/or the second filtrate to obtain a first mixed gas and a fourth mixture;

the volatilization device is used for volatilizing the third mixture in inert gas to obtain second mixed gas and black powder;

a post-treatment device, configured to perform post-treatment on the fourth mixture to obtain a second lithium salt, calcium fluoride, and calcium phosphate, respectively;

the condensing device is used for condensing the first mixed gas and/or the second mixed gas to obtain a first mixed liquid; wherein the first mixed liquid comprises water and an organic solvent of the electrolyte of the waste lithium ion battery;

the liquid separating device is used for carrying out liquid separating treatment on the first mixed liquid to respectively obtain a second mixed liquid and a third mixed liquid; wherein the volume of the organic solvent in the second mixed solution is larger than that of water, and the volume of the organic solvent in the third mixed solution is smaller than that of water;

and the rectifying device is used for rectifying the second mixed solution to respectively obtain the organic solvent and the water.

In order to solve the problem of environmental pollution caused by improper treatment of the solution in the recovery process in the wet crushing and recovery process of the waste lithium ion battery, the invention has the following advantages:

1 through letting in gas and stirring in the first mixture after with old and useless lithium ion battery wet process breakage, can be from the plastic film quick separation with the electrolyte of adhesion on the plastic film on the one hand like this, the bubble that lets in on the other hand can accelerate the come-up of plastic film to stir and avoid first mixture mutual adhesion, thereby separate the plastic film from first mixture fast, and improve the rate of recovery of plastic film. Therefore, substances polluting the environment on the plastic film can be separated from the plastic film through the solution, and the recycled plastic film is prevented from polluting the environment.

2, carrying out reduced pressure distillation on the first filtrate and the second filtrate in the pretreatment process of the second mixture, and then condensing the distilled first mixed gas to obtain a first mixed solution; separating the first mixed solution to obtain a second mixed solution; and finally, rectifying the second mixed solution to respectively obtain the organic solvent and the water of the electrolyte. Therefore, the liquid in the recovery process can be treated and recovered to obtain the organic solvent and water, and the pollution to the environment is reduced.

And 3, volatilizing the third mixture in the pretreatment process of the second mixture in inert gas to obtain second mixed gas. Therefore, the second mixed gas can be recovered in the same treatment mode as the first mixed gas, and finally the organic solvent and the water are obtained, so that the pollution to the environment is reduced.

Drawings

FIG. 1 shows a schematic diagram of an embodiment of a wet recycling method for waste lithium ion batteries;

FIG. 2 is a schematic diagram illustrating a wet recycling method of waste lithium ion batteries according to another embodiment;

FIG. 3 shows a schematic diagram of an embodiment of a wet recycling apparatus for waste lithium ion batteries;

fig. 4 shows a schematic diagram of a wet recycling device for waste lithium ion batteries according to another embodiment.

The specification refers to the numerals:

21. a crushing device;

22. a buoyancy sorting device;

23. a pretreatment device;

231. a hydrodynamic sorting device;

232. a first filtering device;

233. a wet ball milling device;

234. a screen sorting device;

235. a second filtering device;

24. a reduced pressure distillation device;

25. a volatilization device;

26. a post-processing device;

261. a first reaction filtration device;

262. a second reaction filtration device;

263. a third reaction filtering device;

27. a condensing unit;

28. a liquid separating device;

29. a rectification device.

Detailed Description

The disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those of ordinary skill in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the present disclosure.

As used herein, the term "include" and its variants are to be read as open-ended terms meaning "including, but not limited to. The term "based on" is to be read as "based, at least in part, on". The terms "one embodiment" and "an embodiment" are to be read as "at least one embodiment". The term "another embodiment" is to be read as "at least one other embodiment".

The embodiment discloses a wet crushing and recycling method 10 for waste lithium ion batteries, as shown in fig. 1 and fig. 2, which may include steps S11 to S19, and the following respectively describes the steps in detail:

s11, crushing the waste lithium ion battery in a first solution to obtain a first mixture; the first mixture comprises water, an organic solvent of an electrolyte of a waste lithium ion battery and a first lithium salt.

In this embodiment, as shown in fig. 1, in step S11, the waste lithium ion battery may be crushed in the first solution, and the size of the crushed waste lithium ion battery may be 1mm to 30mm. The waste lithium ion battery is crushed in the solution, so that the combustion and explosion conditions of residual electric energy in the battery in the crushing process can be reduced. After the waste lithium ion battery is crushed, the electrolyte in the waste lithium ion battery is mixed with the first solution, and volatilization of an organic solvent in the electrolyte can be reduced, so that pollution of the organic solvent to the environment is reduced. Wherein the first solution may comprise water and/or a mixture in a subsequent step. And crushing the waste lithium ion battery to obtain a first mixture. The first mixture may include water, an organic solvent of an electrolyte of a waste lithium ion battery, and a first lithium salt. Due to different types of crushed waste lithium ion batteries, the first lithium salt can comprise one or more of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium dioxalate borate, lithium bis-fluorosulfonylimide and the like.

And S12, introducing gas into the first mixture, stirring, and performing buoyancy separation to obtain a second mixture and a plastic film respectively.

In this embodiment, as shown in fig. 1, in step S12, gas may be introduced into the first mixture obtained after wet crushing of the waste lithium ion battery, and the first mixture is stirred, so that mutual adhesion between the first mixture can be avoided through stirring, the separation is more thorough, and the electrolyte adhered to the diaphragm is better transferred to the solution; on the other hand, the floating of the plastic film can be accelerated by the introduced bubbles. Thereby rapidly separating the plastic film from the first mixture and improving the recovery rate of the plastic film. The step S12 may include steps S121 to S123, which are described in detail below:

as shown in fig. 2, in step S121, the first mixture may be fed into the buoyancy sorting device 22, wherein a plurality of rows of exhaust holes are formed at the bottom of the buoyancy sorting device 22, and the distance between the exhaust holes may be 3cm to 30cm. And introducing flow of 20-300L/min into each exhaust hole, so that bubbles which roll and rise can be formed in the first mixture, the bubbles can be adsorbed on the surface of the plastic film, the floating of the plastic film is accelerated, and the plastic film is separated from the first mixture. In step S122, the first mixture may be further stirred at a low speed, so as to prevent the components of the first mixture from adhering to each other, and then gas is introduced at the same time, so that the separation efficiency and the recovery rate of the plastic film are higher. In step S123, the floating plastic film is separated from the first mixture by the separation blade of the buoyancy separation device 22, so as to obtain a second mixture and a plastic film, respectively. In other embodiments, the plastic film separated in step S123 may be cleaned separately, so that the electrolyte remaining on the plastic film may be cleaned to prevent environmental pollution. The cleaning solution can be used as the first solution in the step S11, so that the recycling cost is reduced and the environment is protected.

And S13, pretreating the second mixture to obtain a shell, a pile head, first filtrate, second filtrate, copper foil, aluminum foil and a third mixture.

In this embodiment, as shown in fig. 1, in step S13, the second mixture may be pretreated to obtain a shell, a pile head, a first filtrate, a second filtrate, a copper foil, an aluminum foil, and a third mixture. Thus, the shell, the pile head, the copper foil and the aluminum foil in the second mixture can be recovered, and the first filtrate, the second filtrate and the third mixture can be obtained simultaneously. Therefore, the first filtrate, the second filtrate and the third mixture can be conveniently treated in the subsequent steps, and the pollution to the environment is reduced. The step S13 may include steps S131 to S135, which are described in detail below.

As shown in fig. 2, in step S131, the second mixture may be subjected to hydrodynamic sorting, and the dense substances are separated from the dense substances including the housing and the pile head by the water flow, so as to obtain a first pre-treatment mixture and a second pre-treatment mixture, respectively, wherein the first pre-treatment mixture includes the housing and the pile head. Meanwhile, electrolyte and other substances adhered to the shell and the pile head can be cleaned into the second pretreatment mixture in the process of separating the substances driven by the water flow, so that the pollution to the environment caused by the electrolyte remained on the shell and the pile head obtained by recycling is avoided. In step S132, the second pretreatment mixture may be filtered to obtain a first filtrate and a third pretreatment mixture. Therefore, solid-liquid separation can be carried out on the second pretreatment mixture, and the third pretreatment mixture and the first filtrate can be conveniently and independently treated in the subsequent steps. Step S133, mixing the third pretreatment mixture with the second solution in a weight ratio of 1: mixing the raw materials at a speed of 100 to 500 rpm for 20 to 120 minutes, and ball-milling the mixture. Thus, the electrode powder in the positive and negative electrode plates can be stripped from the current collector to finally obtain the fourth pretreatment mixture. The positive and negative electrode powder and the current collector in the positive and negative electrode plates are separated by adding water and performing wet ball milling, and the positive and negative electrode powder can be finely ground, and the copper aluminum foil cannot be ground in the process, so that the screening is facilitated. Compared with other wet stripping technologies, dilute acid is not required to be added as a stripping agent in the ball milling process in the embodiment, and the dilute acid can cause valuable metals in the anode powder to be dissolved out, so that the subsequent treatment difficulty and cost are increased, the recovery rate is reduced, and the wet ball milling is more environment-friendly. In step S134, the fourth pretreatment mixture may be subjected to screen separation to separate the foil-shaped copper and aluminum from the powdery sixth pretreatment mixture. Wherein, the fifth pretreatment mixture comprising the copper foil and the aluminum foil can be further subjected to gravity separation to respectively obtain the copper foil and the aluminum foil. In other embodiments, the fifth pretreatment mixture may be further washed in water before gravity separation, and the washed solution may be used as the second solution for ball milling and recycling, thereby reducing the cost. In step S135, the sixth pretreatment mixture may be filtered to obtain a second filtrate and a third mixture. Therefore, solid-liquid separation can be performed on the sixth pretreatment mixture, and the third mixture and the second filtrate can be conveniently and independently treated in the subsequent steps.

And S14, carrying out reduced pressure distillation on the first filtrate and/or the second filtrate to obtain a first mixed gas and a fourth mixture.

In this embodiment, as shown in fig. 1, in step S14, the first filtrate and/or the second filtrate may be subjected to distillation under reduced pressure. And (3) carrying out reduced pressure distillation at the temperature of 30-150 ℃ and the pressure of 0.01-0.1MPa, so that water in the first filtrate and/or the second filtrate and an organic solvent of the electrolyte can be separated out in a gaseous state, and the environmental pollution during the subsequent treatment of the fourth mixture is reduced. The separated organic solvent in the first mixed gas can be further recycled in the subsequent steps, so that resource waste is avoided and environmental pollution is reduced.

And S15, volatilizing the third mixture in inert gas to obtain second mixed gas and black powder.

In this embodiment, as shown in fig. 1, in step S15, the third mixture may be volatilized in an inert gas. And volatilizing the mixture at the temperature of 50-200 ℃ for 20-180min, so that the water and the organic solvent of the electrolyte remained in the third mixture are changed into gas and separated. The obtained third mixture does not contain volatile organic solvent, so that the environmental pollution caused by the subsequent treatment of the third mixture is reduced. The separated organic solvent in the second mixed gas can be further recycled in the subsequent steps, so that the environmental pollution is reduced. The inert gas can prevent the metal ions in the third mixture from being oxidized, so that the subsequent treatment difficulty is not increased. Wherein the inert gas comprises one or more of nitrogen, helium, argon and carbon dioxide.

And S16, carrying out post-treatment on the fourth mixture to respectively obtain a second lithium salt, calcium fluoride and calcium phosphate.

In this embodiment, as shown in fig. 1, in step S16, the fourth mixture may be post-treated, so that the lithium element, the fluorine element, and the phosphorus element in the fourth mixture can be recovered, the recovery efficiency is increased, and the environmental pollution caused by the fluorine element and the phosphorus element is reduced. The step S16 may include steps S161 to S163, which are described in detail below:

as shown in fig. 2, in step S161, an acid solution may be added to the fourth mixture to dissolve. Because part of lithium hexafluorophosphate of the waste lithium ion battery is decomposed into lithium fluoride in the process of treating the aqueous solution or in the process of reduced pressure distillation. The lithium fluoride in the fourth mixture can be dissolved by adding the acid solution and then filtered, and impurities which cannot be dissolved in the fourth mixture are discharged, so that the recovery rate and the purity of the lithium are improved. The first post-treatment solution obtained after filtration can be used again to dissolve the fourth mixture. After the concentration of lithium ions in the first post-treatment solution reaches a set value, the next treatment is carried out, so that the efficiency of recovering lithium ions can be improved. In step S162, a soluble carbonate and/or a soluble phosphate may be added to the first post-treatment solution obtained in step S161, and the reaction may be performed at a temperature of 30 ℃ to 99 ℃, so that a second lithium salt precipitate including lithium carbonate or lithium phosphate may be obtained. And filtering the reacted mixture to respectively obtain a second lithium salt and a second post-treatment solution. In step S163, calcium hydroxide may be added to the second post-treatment solution for reaction, and calcium fluoride, calcium phosphate, and the third post-treatment solution are obtained through filtration. The third post-treatment solution can be used as the first solution in the step S11, so that the recovery cost is reduced.

S17, condensing the first mixed gas and/or the second mixed gas to obtain a first mixed solution; wherein, the first mixed liquid comprises water and an organic solvent.

In the present embodiment, as shown in fig. 1, in step S17, the first mixed gas and/or the second mixed gas may be condensed. And changing the first mixed gas and/or the second mixed gas into water and an organic solvent at the condensation temperature of-20 to 20 ℃. Thus, the obtained first mixed solution can be further recycled to respectively obtain water and the organic solvent, thereby reducing the pollution of the organic solvent to the environment.

Step S18, carrying out liquid separation treatment on the first mixed solution to respectively obtain a second mixed solution and a third mixed solution; the volume of the organic solvent in the second mixed solution is larger than that of the water, and the volume of the organic solvent in the third mixed solution is smaller than that of the water.

In this embodiment, as shown in fig. 1, in step S18, the first mixed solution may be subjected to a liquid separation process. This allows the water and the organic solvent mixed solution to be preliminarily separated to obtain the organic solvent containing a small amount of water (i.e., the second mixed solution) and the water containing a small amount of organic solvent (i.e., the third mixed solution). This facilitates further processing of the second mixed liquor. The third mixed solution can be used as the first solution in step S11, reducing the recovery cost.

And S19, rectifying the second mixed solution to respectively obtain an organic solvent and water.

In this embodiment, as shown in fig. 1, in step S19, the second mixed liquid may be rectified. The organic solvent and the water can be respectively obtained at the temperature of 30 to 150 ℃. The organic solvent is obtained by recycling, so that the recycling benefit is increased, and the pollution of the organic solvent to the environment is reduced.

In some embodiments, the second solution in step S133 comprises water and/or a second filtrate.

In this embodiment, the second solution in step S133 may include water and/or a second filtrate. In other embodiments, the second filtrate may be used as the second solution. The amount of the lithium salt and the organic solvent in the second filtrate can be increased by mixing the second filtrate with the third pretreatment mixture, performing ball milling, and recycling for multiple times. This facilitates the recovery of the lithium salt and the organic solvent in the subsequent step of the second filtrate, thereby improving the recovery efficiency and reducing the recovery cost.

In some embodiments, the first solution in step S11 includes one or more of water, the first filtrate, the third mixed solution, and the third post-treatment solution.

In this embodiment, the first solution in step S11 may include one or more of water, the first filtrate, the third mixed solution, and the third post-treatment solution. In other embodiments, the first solution may include one or more combinations of the first filtrate, the third mixed liquor, and the third post-treatment solution. The amount of lithium salt and organic solvent in the first filtrate can be increased by recycling one or more of the first filtrate, the third mixed solution, and the third post-treatment solution in combination for multiple times. This facilitates recovery of the lithium salt and the organic solvent in the subsequent step of the first filtrate, thereby improving recovery efficiency and reducing recovery cost.

The comparative example of the wet crushing recovery method of the waste lithium ion battery is as follows:

example 1:

s11, crushing 1t of waste lithium ion batteries in a first solution to obtain a first mixture;

step S12, stirring (not introducing gas) in the flotation device in the first mixture, scraping and separating the floating diaphragm to respectively obtain a second mixture and a plastic film;

step S131, performing hydrodynamic sorting on the second mixture to respectively obtain 130kg of first pretreatment mixture and second pretreatment mixture containing positive and negative pole pieces; wherein the first pretreatment mixture comprises a shell and a pile head;

step S132, filtering the second pretreatment mixture to obtain a first filtrate and a third pretreatment mixture containing positive and negative pole pieces;

step S133, mixing the third pretreatment mixture with water according to a weight ratio of 1;

step S134, screening the fourth pretreatment mixture to obtain 140kg of a fifth pretreatment mixture and a sixth pretreatment mixture; wherein the fifth pretreatment mixture comprises copper foil and aluminum foil;

step S135, filtering the sixth pretreatment mixture to obtain a second filtrate and a third mixture;

step S14, carrying out reduced pressure distillation on the first filtrate and/or the second filtrate at 90 ℃ to obtain a first mixed gas and a fourth mixture;

s15, introducing the third mixture into nitrogen to volatilize for 2 hours at 105 ℃ to obtain second mixed gas and 540kg black powder;

step S161, adding 20wt% of sulfuric acid into the fourth mixture for dissolving, and filtering to obtain a first post-treatment solution;

step S162, adding sodium carbonate into the first post-treatment solution for reaction, and filtering to respectively obtain lithium carbonate and a second post-treatment solution;

step S163, adding calcium hydroxide into the second post-treatment solution for reaction, and filtering to obtain calcium fluoride, calcium phosphate and a third post-treatment solution; reusing the third post-treatment solution to a wet crushing procedure;

s17, condensing the first mixed gas and/or the second mixed gas at 5 ℃ to obtain a first mixed solution; wherein the first mixed liquid comprises water and an organic solvent;

step S18, carrying out liquid separation treatment on the first mixed solution to respectively obtain a second mixed solution and a third mixed solution; the volume of the organic solvent in the second mixed solution is larger than that of the water, and the volume of the organic solvent in the third mixed solution is smaller than that of the water;

Example 2:

s12, stirring the first mixture in a flotation device, bubbling upwards through air holes at the bottom of the flotation device at the flow rate of 100L/min to enable a diaphragm to continuously float upwards, and scraping and separating the floating diaphragm to obtain a second mixture and a plastic film respectively;

recycling the first filtrate obtained in the step S132 to the wet crushing process in the step S11, and recycling for 5 times; reusing the second filtrate obtained in the step S135 to the wet ball milling process in the step S133, and recycling for 5 times; the other steps are the same as in example 1.

Example 3:

s12, stirring the first mixture in a flotation device, bubbling upwards through air holes in the bottom of the flotation device at the flow rate of 150L/min to enable a diaphragm to continuously float upwards, and scraping and separating the floating diaphragm to obtain a second mixture and a plastic film respectively;

recycling the first filtrate in the step S132 to the wet crushing procedure in the step S11, and recycling for 10 times; recycling the second filtrate obtained in the step S135 to the wet ball milling process in the step S133, and recycling for 10 times; the other steps are the same as in example 1.

Example 4:

s12, stirring the first mixture in a flotation device, bubbling upwards through air holes in the bottom of the flotation device at the flow rate of 200L/min to enable a diaphragm to continuously float upwards, scraping and separating the floating diaphragm to obtain a second mixture and a plastic film respectively;

recycling the first filtrate obtained in the step S132 to the wet crushing process in the step S11, and recycling for 20 times; the second filtrate in the step S135 is reused in the wet ball milling process in the step S133, and is recycled for 20 times; the other steps are the same as in example 1.

Washing and drying the membranes recovered in the embodiments, and calculating the recovery rate; the lithium carbonate powder after crystallization was weighed, and the recovery rate of lithium was calculated.

The results are given in the following table:

table 1: diaphragm recovery rate statistical table

Table 2: statistical table of lithium and organic solvent recovery rates

The comparative analysis of the above examples shows that:

1. it can be seen from the examples in table 1 that the separation efficiency and recovery rate of the membrane can be greatly improved by stirring and introducing gas in the flotation process, and the main reason is that in the bubble rising process, the porous membrane saturated by water is enabled to obtain buoyancy so as to rise quickly, so that the purpose of high-efficiency separation is achieved. From the viewpoint of cost, the amount of air flow needs to be controlled within a suitable range.

2. It can be seen from the examples in table 2 that, after the first filtrate and the second filtrate are recycled for a certain number of times, the recovery rates of lithium and the organic solvent are high, and the reason for this is that the content of lithium salt and the organic solvent in the filtrate after the first filtrate and the second filtrate are recycled is increased, so that the lithium salt and the organic solvent are easier to separate in the subsequent process, and the recovery rate is higher; however, the recovery rate of lithium in the filtrate is correspondingly reduced along with the continuous increase of the application times, because the concentration of the filtrate is increased after the continuous application, the lithium salt remained in the black powder is increased, and the lithium salt can be recovered together with the black powder, so that the waste of resources can not be caused.

Based on the same inventive concept, the present disclosure further provides a wet crushing and recycling device 20 for waste lithium ion batteries, which is used for recycling the waste lithium ion batteries in a harmless manner, and as shown in fig. 3, the wet crushing and recycling device may include:

the crushing device 21 is used for crushing the waste lithium ion batteries in the first solution to obtain a first mixture; the first mixture comprises water, an organic solvent of an electrolyte of a waste lithium ion battery and a first lithium salt.

In this embodiment, the crushing device 21 may be configured to contain the waste lithium ion battery and the first solution, crush the waste lithium ion battery to a crushed material with a size of 1mm to 30mm. The crushing device 21 may include a multistage crusher, and crush the waste lithium ion battery for multiple times to obtain a first mixture with a size meeting the requirement; the first mixture comprises water, an organic solvent of an electrolyte of a waste lithium ion battery and a first lithium salt.

And the buoyancy sorting device 22 is used for introducing gas into the first mixture, stirring the gas and obtaining a second mixture and a plastic film respectively through buoyancy sorting.

In this embodiment, the first mixture may be introduced into the buoyancy sorting device 22, and the large air vent provided at the bottom of the buoyancy sorting device 22 discharges air bubbles, and the air bubbles roll and rise in the first mixed liquid. Meanwhile, the stirrer of the buoyancy sorting device 22 stirs the first mixture, so that mutual adhesion among the first crushed material components is avoided, the introduced bubbles can accelerate the floating of the plastic film, and the separation efficiency and the recovery rate are improved. And finally, separating the floating plastic film from the first mixture by using a separating scraper of the buoyancy separation device 22 to respectively obtain a second mixture and a plastic film.

And a pretreatment device 23 for pretreating the second mixture to obtain a shell, a pile head, a first filtrate, a second filtrate, a copper foil, an aluminum foil, and a third mixture.

In this embodiment, the pretreatment device 23 is used to pretreat the second mixture to obtain a shell, a pile head, a first filtrate, a second filtrate, a copper foil, an aluminum foil, and a third mixture. Thus, the shell, the pile head, the copper foil and the aluminum foil in the second mixture can be recovered, and the first filtrate, the second filtrate and the third mixture can be obtained simultaneously. Therefore, the first filtrate, the second filtrate and the third mixture can be conveniently treated in the subsequent steps, and the pollution to the environment is reduced. As shown in fig. 4, the pretreatment device 23 may include: a hydrodynamic sorting device 231, a first filtering device 232, a wet ball milling device 233, a screen sorting device 234, and a second filtering device 235. The hydrodynamic sorting device 231 can separate the low-density substances from the high-density substances including the housing and the pile head under the driving of the water flow, so as to obtain a first pre-treatment mixture and a second pre-treatment mixture, respectively, wherein the first pre-treatment mixture includes the housing and the pile head. The first filtering device 232 may filter the second pretreatment mixture to obtain a first filtrate and a third pretreatment mixture. Therefore, solid-liquid separation can be carried out on the second pretreatment mixture, and the third pretreatment mixture and the first filtrate can be conveniently and independently treated in the subsequent steps. The wet ball milling device 233 may perform ball milling after mixing the third preliminary treatment mixture with the second solution. Thus, the electrode powder in the positive and negative electrode plates can be stripped from the current collector to finally obtain the fourth pretreatment mixture. The screen sorting device 234 may screen-sort the fourth preliminary mixture to separate the foil-like copper and aluminum from the powdery sixth preliminary mixture. The second filtering device 235 may filter the sixth pretreatment mixture to obtain a second filtrate and a third mixture. Therefore, solid-liquid separation can be performed on the sixth pretreatment mixture, and the third mixture and the second filtrate can be conveniently and independently treated in the subsequent steps.

And a reduced pressure distillation device 24 for performing reduced pressure distillation on the first filtrate and/or the second filtrate to obtain a first mixed gas and a fourth mixture.

In this embodiment, the vacuum distillation apparatus 24 may separate the water and the organic solvent of the electrolyte in the first filtrate and/or the second filtrate into a gaseous state at a temperature of 30 to 150 ℃ and a pressure of 0.01 to 0.1mpa.

And the volatilizing device 25 is used for volatilizing the third mixture in inert gas to obtain second mixed gas and black powder.

In this embodiment, the volatilizing device 25 may volatilize the third mixture at 50 to 200 ℃ for 20 to 180min in an inert gas, so that the residual water in the third mixture and the organic solvent of the electrolyte may be separated into a gaseous state.

And a post-treatment device 26 for post-treating the fourth mixture to obtain a second lithium salt, calcium fluoride and calcium phosphate.

In this embodiment, the post-treatment device 26 can post-treat the fourth mixture, so as to recover the lithium element, the fluorine element and the phosphorus element in the fourth mixture, increase the recovery efficiency and reduce the pollution of the lithium element, the fluorine element and the phosphorus element to the environment. As shown in fig. 4, the post-processing device 26 may include: a first reaction filtering device 261, a second reaction filtering device 262 and a third reaction filtering device 263. The first reaction filtering device 261 may add an acid solution to the fourth mixture to dissolve, so that lithium fluoride in the fourth mixture may be dissolved; the dissolved solution can then be filtered to remove insoluble impurities from the fourth mixture, which facilitates the improvement of the purity of the subsequent recovered material. The second reaction filtering device 262 may add soluble carbonate and/or soluble phosphate to the first post-treatment solution obtained from the first reaction filtering device 261, and react at a temperature of 30 to 99 ℃, so that a second lithium salt precipitate including lithium carbonate or lithium phosphate may be obtained. The reacted mixture may be filtered to obtain the second lithium salt and the second post-treatment solution, respectively. The third reaction filtering device 263 can add calcium hydroxide into the second post-treatment solution for reaction, and obtain calcium fluoride, calcium phosphate and the third post-treatment solution after filtration.

The condensing device 27 is used for condensing the first mixed gas and/or the second mixed gas to obtain a first mixed liquid; wherein the first mixed liquid comprises water and an organic solvent of the electrolyte of the waste lithium ion battery.

In the present embodiment, the condensing device 27 may condense the first mixed gas and/or the second mixed gas. And changing the first mixed gas and/or the second mixed gas into water and an organic solvent at the condensation temperature of-20 to 20 ℃.

A liquid separating device 28, configured to perform liquid separating treatment on the first mixed liquid to obtain a second mixed liquid and a third mixed liquid, respectively; the volume of the organic solvent in the second mixed solution is larger than that of the water, and the volume of the organic solvent in the third mixed solution is smaller than that of the water.

In this embodiment, the liquid separation device 28 may perform liquid separation processing on the first mixed liquid. This allows the water and the organic solvent mixed solution to be preliminarily separated to obtain the organic solvent containing a small amount of water (i.e., the second mixed solution) and the water containing a small amount of organic solvent (i.e., the third mixed solution).

And the rectifying device 29 is used for rectifying the second mixed solution to respectively obtain the organic solvent and the water.

In this embodiment, the rectification device 29 may rectify the second mixed liquid. The organic solvent and the water can be respectively obtained at the temperature of 30 to 150 ℃.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific to implementations of the present disclosure and that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure in practice.

Claims

1. A wet crushing and recycling method for waste lithium ion batteries is characterized by comprising the following steps:

step S13, performing pretreatment on the second mixture to obtain a shell, a pile head, first filtrate, second filtrate, copper foil, aluminum foil and a third mixture; wherein the step S13 includes:

step S134, screening the fourth pretreatment mixture by using a screen to obtain a fifth pretreatment mixture and a sixth pretreatment mixture; wherein the fifth pretreatment mixture comprises the copper foil and the aluminum foil;

step S135, filtering the sixth pretreatment mixture to obtain the second filtrate and the third mixture;

2. The wet crushing recovery method for the waste lithium ion batteries according to claim 1, wherein the temperature of the reduced pressure distillation in the step S14 is 30 to 150 ℃, and the pressure of the reduced pressure distillation is 0.01 to 0.1MPa.

3. The wet crushing recovery method for the waste lithium ion batteries according to claim 1, wherein the volatilization temperature in the step S15 is 50 to 200 ℃, and the volatilization time is 20 to 180min.

4. The wet crushing recovery method for the waste lithium ion batteries according to claim 1, wherein the temperature of rectification in the step S19 is 30 to 150 ℃.

5. The wet crushing and recycling method for waste lithium ion batteries according to claim 1, wherein the step S12 comprises:

6. The wet crushing recovery method for waste lithium ion batteries according to claim 1, wherein in the step S133, the weight ratio of the third pretreatment mixture to the second solution is 1:1 to 10, the ball milling time is 20 to 120 minutes, and the ball milling speed is 100 to 500 revolutions per minute.

7. The wet crushing recovery method for waste lithium ion batteries according to claim 1 or 6, wherein the second solution in step S133 comprises water and/or the second filtrate.

8. The wet crushing recovery method for waste lithium ion batteries according to claim 1, wherein the step S16 comprises:

9. The wet crushing recovery method for waste lithium ion batteries according to claim 8, wherein the first solution in step S11 comprises one or more of water, the first filtrate, the third mixed solution, and the third post-treatment solution.

10. The wet crushing recovery method for waste lithium ion batteries according to claim 1, wherein the inert gas in step S15 comprises one or more of nitrogen, helium, argon and carbon dioxide.

11. The wet crushing recovery method for waste lithium ion batteries according to claim 1, wherein the condensation temperature in the step S17 is-20 to 20 ℃.

12. A wet crushing and recycling device for waste lithium ion batteries, wherein the wet crushing and recycling device for waste lithium ion batteries performs a wet crushing and recycling method for waste lithium ion batteries according to any one of claims 1 to 11, and comprises:

the crushing device is used for crushing the waste lithium ion battery in the first solution to obtain a first mixture; wherein the first mixture comprises water, an organic solvent of the electrolyte of the waste lithium ion battery and a first lithium salt;

the pretreatment device is used for pretreating the second mixture to obtain a shell, a pile head, first filtrate, second filtrate, copper foil, aluminum foil and a third mixture; wherein, preceding processing apparatus includes: the device comprises a hydrodynamic force sorting device, a first filtering device, a wet ball milling device, a screen sorting device and a second filtering device; the hydrodynamic sorting device is driven by water flow to separate substances with low density from substances with high density, including the shell and the pile head, so as to respectively obtain a first pretreatment mixture and a second pretreatment mixture, wherein the first pretreatment mixture includes the shell and the pile head; the first filtering device filters the second pretreatment mixture to obtain a first filtrate and a third pretreatment mixture; the wet ball milling device is used for mixing the third pretreatment mixture with the second solution and then carrying out ball milling treatment to obtain a fourth pretreatment mixture; the screen sorting device is used for carrying out screen sorting on the fourth pretreatment mixture to obtain a fifth pretreatment mixture and a sixth pretreatment mixture; wherein the fifth pretreatment mixture comprises the copper foil and the aluminum foil; the second filtering device filters the sixth pretreatment mixture to obtain the second filtrate and the third mixture;

the post-treatment device is used for carrying out post-treatment on the fourth mixture to respectively obtain a second lithium salt, calcium fluoride and calcium phosphate;